CONCORD — Opponents of the Northern Pass transmission project celebrated Thursday as the Site Evaluation Committee unexpectedly voted 7-0 to deny the application.

The committee said earlier in the day that project developer Eversource failed to meet its burden of proof that the project would not negatively impact the orderly development of the region, one of four criteria that must be met for approval.

After the straw vote, the committee continued to review the evidence, but after lunch Vice Chairwoman Kathryn Bailey moved to deny the application because, she said, the committee could not approve the application.

“There are pros and cons to continue the proceedings, but at this point we cannot grant a certificate and there are some risks in continuing deliberations,” Bailey said. “We’ve reached the point where we cannot grant a certificate if everyone votes the way we articulated this morning on orderly development.”

The SEC’s decision ends eight years of controversy and opposition once the 192-mile transmission line from Pittsburg to Deerfield was announced in 2010.

Martin Murray, spokesman for Northern Pass said: “We are shocked and outraged by today’s SEC outcome. The process failed to comply with New Hampshire law and did not reflect the substantial evidence on the record. As a result, the most viable near-term solution to the region’s energy challenges, as well as $3 billion of New Hampshire job, tax, and other benefits, are now in jeopardy. Clearly, the SEC process is broken and this decision sends a chilling message to any energy project contemplating development in the Granite State. We will be seeking reconsideration of the SEC’s decision, as well as reviewing all options for moving this critical clean energy project forward.”

Long-time opponent Susan Schibanoff of Easton said: “The SEC did the right thing today by law and by the people of New Hampshire.”

Jack Savage of the Society for the Protection of New Hampshire Forests said the SEC rejected a proposal that has had fundamental flaws since the beginning. “That is why they could not make their case,” he said.

Eversource has 30 days after the SEC issues a written decision to ask for a rehearing or to reconsider its vote. If that is granted, a rehearing would be held before the SEC, said attorney Michael Iacopino, but if it is denied, Eversource would have 30 days to appeal the decision to the Supreme Court, which would determine whether it was unreasonable or unlawful.

Depending on the court’s decision, Iacopino said, the SEC could rehear the case and may have to go back to the beginning and start over. “We’ll do what the court says,” he said.

Northern Pass was recently selected as the sole of 46 proposals to provide 1,200 megawatts of renewable electricity for Massachusetts Clean Energy Project and has two months to negotiate contracts with that state’s utilities before going before regulators. In announcing the selection, Massachusetts energy officials said one of the key reasons was the project’s ability to begin operations in 2020, at least two years earlier than other proposals.

The SEC earlier this week concluded Eversource has the financial, technical and managerial capability and experience to construct the $1.6 billion project. But members were concerned about the ability to manage any project the size of Northern Pass, saying it would be difficult to ensure requirements and conditions are met during construction.